/**
 * P6Spy
 * <p>
 * Copyright (C) 2002 - 2017 P6Spy
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.p6spy.engine.spy.appender;

import com.p6spy.engine.spy.P6SpyOptions;

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.PrintStream;

/**
 * Appender which writes log messages to a file.  This is the default appended for P6Spy.
 */
public class FileLogger extends StdoutLogger {

    private String fileName = null;
    private PrintStream printStream = null;

    private void init() {
        if (fileName == null) {
            throw new IllegalStateException("setLogfile() must be called before init()");
        }

        try {
            // 防止目录不存在报错！
            // add by SUNHAO 2017-12-26
            if (!new File(fileName).getParentFile().exists()) {
                new File((fileName)).getParentFile().mkdirs();
            }

            printStream = new PrintStream(new FileOutputStream(fileName, P6SpyOptions.getActiveInstance().getAppend()));
        } catch (IOException e) {
            e.printStackTrace(System.err);
        }
    }

    @Override
    protected PrintStream getStream() {
        // Lazy init to allow for the appender to be changed at Runtime without creating an empty log file (assuming
        // that no log message has been written yet)
        if (printStream == null) {
            synchronized (this) {
                if (printStream == null) {
                    init();
                }
            }
        }
        return printStream;
    }

    public void setLogfile(String fileName) {
        this.fileName = fileName;
    }
}

